This invention relates to a ball valve and to a spanner for the ball valve.
A known ball valve has a valve body, a ball closing component, and a valve stem and it is equipped with seal rings mounted to the stem grooves. The ball closing component has a main passage hole which enables flow of an operating medium and, in addition, has passage openings located axially opposite the main hole. There is a rotation limiter, working together with a resistance flange mounted into the body inside the limiter, located on an end of a stem extending outside the body. There is a separate spanner, which is used for opening and closing the above mentioned valve, which, when the valve is used, is installed on the end of the stem. The spanner has a shaft body which has a seating hole and a handle connected firmly to the shaft body.
Construction of the above mentioned valve enables gradual growth of pressure in a gas piping during opening it and a slow fall of pressure while closing because additional holes used and placed in the ball closing component case operating medium flow first through the additional holes and later on through the main hole of the closing component during opening of the valve. But during closing of the valve, after covering the main hole in the closing component, additional holes are opened for a certain time and later on the valve is completely closed. But the spanner used for opening and closing of the ball valve enables effective service of the valve only within the range of two extreme positions e.g. completely opened and completely closed. But it is not adapted to operating the valve in stages of opening where phases of equalization of pressures are taken into account.